Electron-beam-induced current study of electrically active defects in 4H-SiC

Electrically active defects in epitaxial, n-type, 4H-SiC have been investigated by electron-beam-induced current (EBIC) in the scanning electron microscope. Several defects, mainly nanopipes, 6H polytype inclusions and triangular, carrot-like, defects were detected by different techniques, including atomic force microscopy and cathodoluminescence. However, EBIC images reveal that only nanopipes are electrically active. The hole diffusion length (L) was calculated at different temperatures from EBIC line scans recorded in defect-free regions. L values of 3.1+/-0.2 and 4.8+/-0.3 mum were respectively estimated at 295 and 420 K. A strong decrease of the diffusion length was observed in the proximity of the nanopipes.